On 31 August 2006, the Air Force Research Laboratory's Air Vehicles Directorate completed its Automated Aerial Refueling (AAR) Station Keeping Flight Test. This series of flights included the first autonomous flight of an aircraft in the refueling position behind a KC-135 tanker.
The purpose of the AAR program is to develop and demonstrate the capability to perform boom & receptacle refueling of unmanned air vehicle systems with the existing Air Force tanker fleet using operationally representative subsystems. The expected benefits of AAR to UAV operations include: increased combat radius, increased mission time, reduced response time for time-critical targets, reduced need for forward staging areas, and increased in-theater presence. The Station Keeping Flight Test integrates components on both the tanker and receiver aircraft to demonstrate the ability for the receiver aircraft to autonomously hold position relative to the tanker while the tanker executes its standard maneuvers.
During the 15 August 2006 flight, a Learjet acting as a UAV surrogate was manually flown to the contact position behind a KC-135R from the 107th Air Refueling Wing of the New York Air National Guard. During all test flights, Air Force Flight Test Center personnel operated the KC-135. At the contact position where Air Force aircraft could start receiving fuel from the tanker, the Learjet's AAR flight control system was engaged enabling the aircraft to autonomously hold the contact position while the tanker executed both straight and level flight and turns. During the flight, the AAR system was engaged at the contact position for 23 consecutive minutes allowing the Learjet to follow the KC-135 through two full orbits.
Over the next year, the AAR team will build upon the success of the Station Keeping Flight Test towards enabling new automated refueling capabilities. During the August 2007 flight test, the AAR team will demonstrate autonomous maneuvering around the tanker. The Learjet will engage the AAR system at the observation position on the tanker wing and be directed from a control station to go to the pre-contact and contact positions upon approval from the tanker crew. This test will be combined with simulations of both multi-ship operations around the tanker and long distance tanker rendezvous to demonstrate that the AAR capability is ready for transition from the Learjet testbed to Air Force assets.
The AAR team includes a diverse set of government and contractor organizations. The government team includes the Air Vehicles, Sensors, Human Effectiveness and Information Directorates at the Air Force Research Laboratory, the Air Force Flight Test Center and Air Force Test Pilot School at Edwards AFB, Naval Air Systems Command (NAVAIR), the 107th Air Refueling Wing, 827th Aircraft Sustainment Group at Tinker AFB, DARPA Information Exploitation Office, Aeronautical Systems Center, Air Mobility Command, and Air Combat Command. On the contractor side of the team, Calspan operates the Learjet; Rockwell Collins supports KC-135 operations and builds the Tactical Targeting Network Technologies datalink; L3 Communications, SySense and the Illinois Institute of Technology work with NAVAIR developing the precision global positioning system based relative navigation system; Boeing built the AAR flight control computer and developed the station keeping control laws; Northrop Grumman built the GPS receivers and developed an EO/IR position sensing system; General Dynamics Advanced Information Systems provides systems engineering and flight test management assistance; Syngenics coordinates the AAR trade studies; Bihrle Applied Research integrates simulations environments; the Institute for Scientific Research develops image processing algorithms; and Coherent Solutions developed the required navigation performance.